Generally, acrylonitrile-butadiene-styrene resin (hereinafter, referred to as ‘ABS resin’) has been widely used as an exterior material for electric/electronic products, office appliances, etc., by having excellent stiffness and chemical resistance due to acrylonitrile component and excellent workability and mechanical strength due to styrene component. However, the ABS resin is easily combustible and therefore, has a problem of vulnerability to a fire.
Therefore, the ABS resin used for the electric/electronic products, the office appliances, etc., should have predetermined flame resistance (flame retardant standard) so as to ensure flame resistance.
Examples of a method for providing flame resistance to the ABS resin may include a method of adding and polymerizing flame resistance monomer when preparing rubber-modified styrene resin, a method of mixing flame retardant and auxiliary flame retardant with prepared rubber-modified styrene resin, etc.
The flame retardant may be largely classified into halogen-containing flame retardants and halogen-free flame retardants. Examples of the halogen-free flame retardant may include nitrogen-containing flame retardant and hydration containing flame retardant, etc.
The halogen-free flame retardant is much poorer in flame retardant efficiency than the halogen-containing flame retardant. Therefore, a relatively larger amount of halogen-free flame retardant is used, which degrades mechanical properties of the rubber modified styrene resin. Therefore, the most widely accepted method for providing the flame resistance to the ABS resin at the moment uses the halogen-containing flame retardant.
The halogen-containing flame retardants improve flame resistance while maintaining the mechanical properties of the rubber modified styrene resin. Among others, brominated flame retardant is particularly effective.
However, the currently available ABS resin with flame resistance has significantly poor scratch resistance due to properties of butadiene rubber, and therefore high gloss products are easily scratched. In fact, most flame-retardant ABS resins available today have very poor scratch resistance, i.e., pencil hardness of about 3B or 4B.
Therefore, a need exists for the development of an ABS resin having excellent flame resistance while maintaining excellent scratch resistance, impact strength, and fluidity.